The present invention relates to a condenser, and, more particularly to, an improvement in a condenser for steam turbine.
Hitherto, the combined plant, in which a steam turbine is driven by making use of the waste heat from a gas turbine, generally relies on only the deaerating function of a condenser itself, without providing any independent deaerator.
The U.S. Heat Exchange Institute has recommended that the oxygen content in the condensate in the condenser should be 0.03 cc/l. The condenser of the above type requires about one hour until the oxygen content in the condensate reaches 0.03 cc/l under normal starting conditions (i.e., the time required for deaeration).
For a reduction in the time required for starting of the combined plant, it is necessary to improve the deaerating performance of the condenser itself. For this purpose, it is desirable to replace the condensate in the hot well part in the condenser by a deaerated condensate as quickly as possible.
In the condenser for nuclear apparatus, on the other hand, the path, through which the dropping condensate formed in the cooling pipe nest in the condenser flows to reach the outlet of the hot well part, is elongated in order to lengthen the radioactivity attenuation time of the condensate. In addition, the cooling pipe nest and the hot well part in the condenser are divided from each other by means of a partition plate, and a plurality of vertical partition plates are disposed in the hot well part to make the condensate meander in the condensate passage.
Also in the above condenser, however, a high-oxygen content gas resides in the atmosphere above the condensate in the hot well part. Consequently, while the condensate is meandering in the hot well part, oxygen dissolves into the condensate again, resulting in a rise in the oxygen concentration in the condensate, undesirably.
Thus, the condenser requires a considerable time for deaeration of the condensate in the hot well part, and, disadvantageously a long period of time is required for starting of the whole plant.
Accordingly, it is an object of the invention to provide a condenser capable of expelling the the high-oxygen content gas in the atmosphere in the hot well part to scavenge the same thereby allowing a reduction in the time required for deaeration.
It is another object of the invention to provide a condenser capable of preventing oxygen from redissolving into the condensate in the hot well part thereby allowing an improvement in deaeration performance.
To these ends, according to the invention, a scavenging means is provided for effecting scavenging by steam introduced into the atmosphere in the condensate passage in the hot well part. Since the high-oxygen content gas in the atmosphere in the hot well part is expelled by the scavenging means employing steam, it is possible to reduce the time required for deaeration in the condenser. Moreover, the scavenging means prevents the residence of any high-oxygen content gas in the atmosphere in the hot well part; therefore, there is no possibility that oxygen may redissolve into the condensate so that it is possible to improve the deaeration performance of the condenser.